Conclusions:

The authors concluded that among patients with OSA, those with hypercapnia are at increased risk for postoperative complications when compared to OSA alone.

Perspective:

Significant risk for postoperative complications exists among the OSA population. Severity of OSA was not associated with higher risk of postoperative complications; rather, hypercapnia was found to increase this risk among patients with OSA. Since AHI, a measure of OSA severity, is comprised of both hypopneas and apneas, the populations with mild, moderate, and severe OSA contain a spectrum of heterogeneity not originally considered. When risk-stratifying patients before surgery, clinicians should have a high index of suspicion for OSA, based on standard screening tools, especially if high preoperative serum bicarbonate (compensatory metabolic alkalosis associated with respiratory acidosis from arterial hypercapnia) is measured.